17 Hornet Case Concentricity Issues

[SoonerEd]

Hello All,

I'm new to this forum, as I only recently found it, but not new to reloading. I recently purchased a Sinclair concentricity gauge w/ a 1000 dial indicator. This tool seems to both be helping me in my reloading while also exposing some things that are frustrating me.

In reloading for a CZ 527 17 Hornet, I'm having some concentricity issues. The brass is fully prepped including skimming neck turned to .010. This puts the neck thickness to between .009 and .010. Only skimming which varies between 30% to sometimes 90% turned.

Run-out on loaded rounds with either 20 gr Berger Match Varmit or Nosler Varmagedon's are from .001 to .006. I'm trying to keep them in the .002 range and under which my understanding is where I would like to try and be. I think I found the source of the problem but would like to get suggestions, feedback, etc.

Fully prepped cases are fire formed. When put on the concentricity guage after firing the necks are less than .001 run-out. So, I'm concluding my chamber and bore are on center.

After I run my case through a Redding neck sizing die (not a bushing die) and put it on the guage, the neck run-out goes to no less than .003 and some are worse. So, I've concluded the issue is in the die or press. The press I have is a Rock Chucker from the 70's. I let the shell holder float without the retaining spring so it can at least center front to back on the press.

I can't seem to find a floating expander for a 17 Hornet, nor a Redding or Forster bushing die that would help with better centering the neck sizing operation. Anyone have suggestions on 1) if it sounds like I've correctly narrowed down the source of the problem, 2) how to check the ram in my Rock Chucker to make sure it's not the problem, 3) Would a Forster Co-Ax press be a solutions, 4) sources for a floating button on my neck die or Redding bushing die and would they help, 5) other suggestions.

BTW I have a Wilson Seater that had to be special ordered for this caliber that should address adding to the problem during the seating operation.

I did do a search on this and read different items in the forum but didn't find an answer that specifically addresses my questions.

Thanks for any suggestions.

 

[snert]

When you fire a cartridge in a good chamber, it tends to come out with no runout. However, when you run brass thru a die, even a good one, and the BRASS has inconsistencies in the BODY it transfers to the neck and you get run-out. Even when you turn the neck.

I will get a lot of flak for what I am going to suggest next, but...

Spend more time reading wind and popping primers and you will overcome the difference of that few thousandths in run-out. No disrespect meant at all by this...it is just that chasing the concentricity issue when you are shooting a factory gun with so-so brass is really an exercise in frustration.

Just my thoughts from here,

Snert

 

[MrUnderwood08]

I don't know if you have found the source of the problem yet but you are starting to unravel the problem. I would run the same die in a friends press with and without the expander ball and check neck outside concentricity.

If using the new press solves it then you know its the press (not something I have heard of before). If running without the expander fixes it then you can continue to look for a floating expander or use a decapping die as a separate operation. I would also use a ball end micrometer to check neck wall thickness and consistency so you know problems on the inside are getting pushed to the outside. If thats the case then even if you have zero run out before loading it will come back after seating.

How much are you having to resize... IE fire formed brass neck diameter versus sized. Also sized versus loaded diameter.

I would look into whidden dies if you need a replacement.

17 Hornet is on a not so short list of cartridges that I want to play with one day. Best of luck and please post updates so everyone can learn from this.

Daniel

 

['Freak]

Snug the die’s locking ring while applying light upwards pressure from the ram to the base of the die so squaring/centering the die in the press’s threads and doing same for the locking ring about the die. If when setting up the die for a proper shoulder bump the die ends up adjusted out too high for the ram to reach, use a machined/ground dead flat, flat washer to take up the space between the top of the shell holder and the bottom of the die.

Lock down the de-cap/expander ball stem using pretty much the same method and for the same reasons. Stop at ~ half way when pulling a sized neck back down over the expander ball. While you got the ball stuck inside the neck, use ram pressure to lift the de-dap/expander stem upwards so the stem’s threads are topped out in the die’s threads. Holding the upwards tension, snug the stem’s locking nut while all the slop is pushed out the threads and the expander ball is captured centered in the case neck.

 

[SoonerEd]

Getting ready to go MOA for the holidays, so I'll these a try and report back in a couple of weeks. Keep the suggestions coming though.

 

[CatShooter]

In reloading for a CZ 527 17 Hornet, I'm having some concentricity issues. The brass is fully prepped including skimming neck turned to .010. This puts the neck thickness to between .009 and .010. Only skimming which varies between 30% to sometimes 90% turned.

Run-out on loaded rounds with either 20 gr Berger Match Varmint or Nosler Varmageddons are from .001 to .006. I'm trying to keep them in the .002 range and under which my understanding is where I would like to try and be. I think I found the source of the problem but would like to get suggestions, feedback, etc.

Fully prepped cases are fire formed. When put on the concentricity gauge after firing the necks are less than .001 run-out. So, I'm concluding my chamber and bore are on center.

After I run my case through a Redding neck sizing die (not a bushing die) and put it on the gauge, the neck run-out goes to no less than .003 and some are worse. So, I've concluded the issue is in the die or press. The press I have is a Rock Chucker from the 70's. I let the shell holder float without the retaining spring so it can at least center front to back on the press.

I can't seem to find a floating expander for a 17 Hornet, nor a Redding or Forster bushing die that would help with better centering the neck sizing operation. Anyone have suggestions on 1) if it sounds like I've correctly narrowed down the source of the problem, 2) how to check the ram in my Rock Chucker to make sure it's not the problem, 3) Would a Forster Co-Ax press be a solutions, 4) sources for a floating button on my neck die or Redding bushing die and would they help, 5) other suggestions.

BTW I have a Wilson Seater that had to be special ordered for this caliber that should address adding to the problem during the seating operation.

I did do a search on this and read different items in the forum but didn't find an answer that specifically addresses my questions.

Thanks for any suggestions.

My first comment is that you are over-thinking this and being OCD to the 5th magnitude. While CZs are noted for their accuracy, this is NOT a benchrest rifle, and you cannot achieve benchrest groups with it.

That being said...

After I run my case through a Redding neck sizing die (not a bushing die) and put it on the gauge, the neck run-out goes to no less than .003 and some are worse. So, I've concluded the issue is in the die or press. The press I have is a Rock Chucker from the 70's. I let the shell holder float without the retaining spring so it can at least center front to back on the press.

The problem is neither.

The standard neck sizing die has NO body support or contact at any point in the sizing cycle - just think about it - it sizes the neck, not the body. You could use a 17 Fireball neck sizer for that matter, the neck sizing die does absolutely NOTHING to keep the body and neck in axial alignment.

It is a big mistake to remove the shell holder retaining clip. When the shell holder is in it's proper place, there is enough play between the case head (extractor groove) and the shell holder, to allow the case to "self center" in a die that DOES size the body... if the shell holder is out of center, it feeds the case into the die, out of center, and that just makes things more worser.

The fact that your RockChucker was made in the 70's is not a negative, it is a better press than the RockChucker you can buy new.

I can't seem to find a floating expander for a 17 Hornet, nor a Redding or Forster bushing die that would help with better centering the neck sizing operation. Anyone have suggestions on 1) if it sounds like I've correctly narrowed down the source of the problem, 2) how to check the ram in my Rock Chucker to make sure it's not the problem, 3) Would a Forster Co-Ax press be a solutions, 4) sources for a floating button on my neck die or Redding bushing die and would they help, 5) other suggestions.

You will not be able to ever find a floating expander, or a bushing die for the 17 Hornet... it is a small game hunting cartridge, and no one will make top-end dies for it.

If concentricity is a concern... the best available solution is to use a quality FL sizing die, and set it so the body is just slightly sized - that will bring you as close to concentricity as you can get... make sure you keep the necks annealed, as the 0.010" necks are fragile and they will split if allowed to get work-hardened.

 

[SoonerEd]

Thanks...got some great suggestions. As far as the OCD, Your on key.

I'll be happy with 1/2 inch groups if that is all I can get but want to improve my understanding of reloading and try to minimize the run-out it possible. Even if I can't improve this gun I want to improve my technique and understanding. So this gives me some things to fiddle with and maybe learn something. I've got a 220 Swift that I'm getting .25 MOA groups but it's not factory. Maybe I can learn something I can apply to my swift.

 

['Freak]

I caught the part about it not being a bushing die but “it’s a neck die” didn’t register. Buy their full length size die and get it setup true in your press and dialed in for your chamber. An o-ring works well as a shell holder retainer.

 

[drichi]

I had the same problem that you are having, I found that I could get very good runout with a Hornady full length die and not my Redding neck die. I also tried a Redding full length die, no better. I did send the neck die to be converted to a bushing die. We will see how that works when I get it back. I was actually a little disappointed that the Redding dies quality seems to be less than the Hornady that I bought first.

 

[CatShooter]

I had the same problem that you are having, I found that I could get very good runout with a Hornady full length die and not my Redding neck die. I also tried a Redding full length die, no better. I did send the neck die to be converted to a bushing die. We will see how that works when I get it back. I was actually a little disappointed that the Redding dies quality seems to be less than the Hornady that I bought first.

Who is converting the die to bushing, and how much are they charging?

 

[artbosco]

Get rid of the half measure and endless headache producing Neck Sizing Die and go to a Full Length Sizing Die.

 

[CatShooter]

Get rid of the half measure and endless headache producing Neck Sizing Die and go to a Full Length Sizing Die.

I have no headaches from neck sizing... I have no head separations either, and cases last forever.

I DO get headaches from my Ex wifie, but I take Advil for those.

 

[drichi]

I had die conversion done by Jim Carstenson, he does nice work. There is an article on 6 br main web site with contact info, die arrived back today.
Takes about 90 days, $50 with return shipping.

 

[wapiti25]

get and use Imperial Dry Neck Lube to use on the inside of the brass neck, it helps the expander button slide thru the neck and not pull the neck crooked. A full length sizing die that is fitted to your chamber is the best way to reload. The neck should only be sized to just hold the bullet, that way the expander is not stretching the neck so much.

 

[searcher]

Unless you can get a custom built die (to fit your fired brass) as your full-length die, I'd work to make your neck die do a better job by doing a tune on it. Check it for mis-alignment and stick the decap assembly in a drill and reduce the O.D. using a fine diamond file, then polishing with a dremel tool as it spins in the chuck until you get a rather light friction fit inside your case mouth. I've had the same problems, especially with my "micro" guns. The force of a slightly mis-aligned expander ball that is larger than needed will only cause you problems - those which can fortunately be greatly reduced or eliminated. Such reduction may cause need for a different bushing to give you the proper neck tension when finished but is far cheaper than another unnessary die. When getting a new sizing die which will use an expander (such as with semi-autos for dent removal), I won't even try it until this procedure is used on it. I also leave the shell-holder circlip off and if you do, it is most important to gently nudge the case to the rear shell holder prior to each case being run up into the ram or you will have bigger problems on those cases that start into the die which are very mis-aligned. The O-ring as another mentioned is good idea - I have used a loose twistie-tie in a pinch. Good luck.

 

[drichi]

I am happy to report that after a die conversion by Mr Carsteson and a redding bushing my runout on 10 cases is .005, money well spent in my book.

 

[drichi]

Whoops, I left one zero out, should be .0005 runout max.

 

[SoonerEd]

Back from vacation and got the holidays behind me so I beginning to experiment with some of the great suggestions. I would like to especially thank OleFreak and CatShooter for their suggestons.

Here is what I have done so far.

1) Removed expander assembly and decapped checking concentricity. I went from ~ .0005 unsized to still being < .001 neck sized.

2) Set the die locking ring and expander locking ring under load as OleFreak suggested. I was getting run-out at this step prior to this up to .006. Resetting my dies run-out is now .002 to .003 on the neck. These cases were ran without and lube either internal or external. There is as much as .001 variance in the brass neck thickness as I only skimmed neck turned so part of the .002 to .003 is explained by neck thickness variance.

3) I also experimented with how dry lube inside and Imperial on the outside might affect concentricity. With the lubed cases, there seemed to be an improvement as most cases were .002 with several in the .001 and only two out of twenty that were at .003. So, it appears lubing helped some.

All interesting lessons. Next step is to try a FL die.

Thanks again all...any additional suggests/comments are welcomed.